This invention relates generally to apparatus for dispensing metered quantities of liquids and, more particularly, to a machine for selectively dispensing specific volumes of colorants used to formulate paints of various color.
In the interest of limiting costly inventories, most retail stores formulate many paint colors at the time of purchase rather than stocking all available colors. The formulation is accomplished by adding specified quantities of colorant tints to a white base paint so as to create the specific color desired. Typically, paints are formulated with apparatus including a plurality of colorant filled containers and pumping mechanisms for withdrawing predetermined quantities therefrom. In the simplest machines of this type, a can filled with the base paint is sequentially moved to each desired colorant container and its individual pump is actuated to withdraw the desired quantity of fluid colorant. A more efficient machine of this type includes a rotary turntable on which the colorant containers are mounted and which is used to sequentially move each colorant container required for the formulation to a given discharge area occupied by the base paint filled can. Although such machines are relatively simple and inexpensive and function satisfactorily for many applications, they exhibit the disadvantage of requiring a substantial amount of attention by an operator thereby adding significant labor cost to the paint sold.
For example, most such machines require a distinct volume setting prior to each pump discharge cycle resulting in a multiplication of individual effort for those numerous instances in which a customer is purchasing several cans of a particular color. Conversely, there exist rather intricate automatic paint colorant machines that will dispense the various tints required for a given formulation in response to a simple set of instructions presented, for example, by the mere insertion of a coded punch card selected by an operator. Although drastically reducing required operator time these machines are too expensive for practical use in most retail outlets and also suffer breakdowns that require complex repairs and often render them dysfunctional for extended periods of time.
The object of this invention, therefore, is to provide a simple paint colorant dispensing machine that limits required operator attention and is in addition reliable and relatively inexpensive.